Category: Winter Storm

Feb 19

All-Access Client Brief: Plowable Snow Moves In Overnight…

Brief: Heavy Snow & Sleet

Forecaster: McMillan

What: Heavy Snow & Sleet

When: 12a to 8a Wednesday

Temperatures: Upper 20s to lower 30s

Wind: E 15-25 MPH

Blowing/ Drifting: Moderate before mixing with sleet

The setup remains the same as a warm front lifts north during the overnight. Copious amounts of moisture will arrive into central Indiana and with cold air in place, a period of moderate to heavy snow will develop. Timing into the city, itself, should come around, or just before, midnight. While the snow will be of the heavy, wet variety, gusty easterly winds will result in blowing and drifting snow (especially on north-south roadways) before precipitation transitions to sleet. We’ve “beefed” our accumulation forecast up to include a 3″ to 5″ band across east-central Indiana, including Indianapolis, as short-term guidance is indicating a period of significant “forcing” (or lift in the atmosphere) that will lead to heavy snowfall rates before the transition to sleet. A couple of hours with snowfall rates in excess of 1″ per hour will likely be observed in that 1a to 3a window. Precipitation will transition to sleet and a period of freezing rain between 3a and 5a from south to north, before turning to all rain in the city before sunrise. Further north, a transition to rain won’t be noticed until after 8a, but the majority of precipitation will likely be over with by that point (just lingering drizzle and fog).

Confidence: High

Permanent link to this article: https://indywx.com/2019/02/19/all-access-client-brief-plowable-snow-moves-in-overnight/

Feb 05

Whole Lot Of Weather Going On…

There’s sure no shortage of active weather, and unfortunately (or fortunately- depending on your perspective), there’s no letup in sight. As we look ahead, we see a fascinating battle of heavyweights set to duke it out for control of our mid and late February pattern. Before we get into some of the longer range model updates, let’s focus on the short and medium term challenges.

Heavy Rain

We continue to target (3) distinct windows where rainfall will be heaviest:

I. Late tonight-Wednesday morning

II. Wednesday night-Thursday morning

III. Thursday evening

In general, widespread 2″ to 2.5″ totals are expected in area rain gauges with heavier amounts across south-central Indiana (where flood risks are highest).

The other item to note? The potential of strong and gusty thunderstorms Thursday afternoon into the early evening. These would be located directly ahead of the cold front. While we’re not anticipating a widespread major event, temperatures and dew points will approach 60 deg. and the atmosphere will be favorable to support a few strong gusts that may mix down to the surface.

Sharply Colder

The cold front that will deliver the heavy rainfall for our midweek will sweep through central Indiana around 4p-5p. Behind the boundary, sharply colder air will blow in on strong and gusty northwest winds Thursday night. Daytime highs (actual highs will occur at midnight Friday) will only top out in the lower 20s with wind chill values in the 0s most of the day.

Winter Threat Late Weekend-Early Next Week?

The fresh batch of cold air in here to wrap up the work week will lay the ground work for potential wintry mischief late weekend into early next week. While the cold still isn’t set to truly establish itself (still think we’re a week-10 days away from that), just enough cold may be around to present the opportunity for an accumulating central and northern Ohio Valley winter threat in the Sunday-Tuesday period. Stay tuned as we fine tune things.

The hesitation that we still have from beginning to “ring the bells” a little louder in the aforementioned period is the position of the high in front of the storm and forecast strongly positive AO. Both of these argue against the idea of this being a widespread wintry event for the southern, and potentially as far north as central Ohio Valley. The early idea here as of now is that we’ll be looking at a wintry mix event to rain for central and southern areas with more of an opportunity for substantial snow across the northern portions of the Ohio Valley. Again, stay tuned as we continue to fine tune things.

Longer term, today’s MJO update continues to take things into Phase 8 and you don’t need us to cover the end result again (think cold) at this point. Should we get the other teleconnections to line-up (AO, PNA, NAO) then a 2-3 week period of significant winter weather would ensue during the 2/20-3/10 timeframe…

Permanent link to this article: https://indywx.com/2019/02/05/whole-lot-of-weather-going-on/

Jan 31

Snowy Thursday Night-Early Friday Morning On Tap…

Brief: Accumulating Snow

Forecaster: McMillan


What: Accumulating snow

When: This evening into the predawn hours Friday

Temperatures: 15 to 18 F

Wind: ESE 5-15 MPH

Blowing/ drifting: Minimal

Attention will shift from the dangerous cold to an accumulating snow event across central and north-central Indiana this evening into the predawn hours Friday. We expect snow to begin reaching the surface (may take a little longer than models suggest due to the dry air in place initially) in western portions of the viewing area between 6p-7p and into central Indiana between 8p and 9p. Heaviest snow still looks to fall during the hours of 10p and 3a. Banding may result in periods of moderate to heavy snow during this time frame. Light snow will be ongoing across southeast Indiana around 7a Friday before departing the state shortly thereafter.

Confidence: High

Next Update: 6:30p Thursday

Permanent link to this article: https://indywx.com/2019/01/31/snowy-thursday-night-early-friday-morning-on-tap/

Jan 24

Long Range: Cold Pattern Isn’t Going Anywhere Fast…

We’ll save our short-term discussions for the severe and high-impact arctic outbreak on deck and focus our attention in this post to the upcoming several weeks. In short, we don’t expect the cold pattern to break anytime soon. Could there be a day or two of “relaxation?” Yes, but from an overall perspective, confidence is higher than normal on the colder than average pattern continuing through the month of February.

Let’s dig in to the teleconnections:

EPO

AO

NAO

PNA


Given the teleconnections in agreement pointing towards a cold pattern, it shouldn’t come as a surprise that the majority of data is also on the cold train as we flip the page into February:

CFSv2 Weeklies

Weeks 1 & 2

Weeks 3 & 4

JMA Weekly

GEFS

While we aren’t licensed to show the European Weeklies, the new update runs with a cold pattern into early March. This falls in line with the overall consensus of longer range data, backed up by teleconnections.

Though not nearly at the amplitude of a few weeks ago, the MJO (Madden-Julian Oscillation) is forecast to move through Phases 5 and 6 in the coming weeks before going back into the “null” phase.


Phases 5 and 6 this time of year would suggest colder anomalies are more likely around our neck of the woods:

Given the above, we continue to think a colder than average “2nd half” of winter looms for the region. We lean heavily on the NAO, EPO, and AO state(s) this time of year and all would point towards a cold time of things moving forward, overall. The latest European Weeklies are interesting from a couple of fronts- initially very cold and then progressively stormy. The idea here is that we remain quite wintry through February and into early March before this pattern breaks. While we may not see a “repeat” visit of the Vortex, it wouldn’t surprise us to see another major arctic outbreak again this winter (after next week), but that likely comes later, and towards the end of the game before we snap into spring.

Buckle up; we think we have a long way to go this winter…

Permanent link to this article: https://indywx.com/2019/01/24/long-range-cold-pattern-isnt-going-anywhere-fast/

Jan 23

Multiple Snow Makers; Pattern Threatens Severe Cold Next Week…

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Permanent link to this article: https://indywx.com/2019/01/23/multiple-snow-makers-pattern-threatens-severe-cold-next-week/

Jan 19

VIDEO: Saturday Night Winter Storm Update…

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Permanent link to this article: https://indywx.com/2019/01/19/video-saturday-night-winter-storm-update/

Jan 19

Blizzard-Like Conditions Develop This Afternoon Into Tonight…

While warm air advection (WAA) created an added challenge this morning (freezing rain north of the city, itself, and rain south of I-70), colder air is working south late this morning and will result in a changeover from freezing rain/ rain to snow over the next couple hours from north to south.

We expect the transition to snow to take place in and around Indianapolis between 1p and 2p.

As upper level energy tracks northeast this evening, strong frontogenesis will help a “deformation band” expand in coverage and intensify across the state.  This will lead to elevated snowfall intensity as the afternoon gives way to evening.  In fact, snowfall rates will likely approach 1″/ hour across central and eastern portions of the state at times during the mid-to-late afternoon and into the evening hours.

8p forecast radar.

As this is taking shape, winds will also begin to crank this afternoon and evening.  Gusts in excess of 50 MPH are expected across central and eastern regions- including Indianapolis.

Obviously this will create concerns for power outages, but the other major worry is for developing blizzard-like conditions and whiteouts through the late afternoon into tonight.

As for snowfall totals, the consensus of latest 12z data continues to support our updated snowfall forecast from this morning.

We’ll have additional updates later this afternoon here on IndyWx.com and on our social media accounts.

To close, we highly encourage not traveling this afternoon.  Conditions are expected to rapidly deteriorate as we move through the next several hours. For many across central and east-central Indiana, roads will likely become impassable by evening with the combination of severe wind gusts and increasing snowfall rates.  Major problems from blowing and drifting snow are expected.

More here in a bit!  Stay safe!

Permanent link to this article: https://indywx.com/2019/01/19/blizzard-like-conditions-develop-this-afternoon-into-tonight/

Jan 19

Winter Storm Update: Significant Impacts Still Expected Later Today…

While the “1st half” of the storm certainly has been a challenge, we still anticipate a high impact situation to develop this afternoon into tonight across the region.

Our updated snowfall forecast:

Saturday morning video update breaking down the details:

Permanent link to this article: https://indywx.com/2019/01/19/winter-storm-update-significant-impacts-still-expected-later-today/

Jan 19

Late Friday Night Update…

A significant winter storm is on our doorstep and will begin to impact all of the region in the coming hours.  Low pressure will continue to deepen as it moves northeast out of Oklahoma, Arkansas, and into Kentucky.  As this takes place, copious amounts of moisture will lift north into central Indiana.  We think precipitation reaches Indianapolis, itself, during the overnight (likely between 3a and 4a).

The bulk of the northern half of the state is still expected to receive predominantly snow with this storm.  However, things get much more tricky along the I-70 corridor (10 to 20 miles either side) as temperatures will be “marginal” early on in the event (aloft and at the surface) and will lead to quite the headache for the first several hours of this storm.  Even as of this update, confidence is low on precipitation type for the I-70 corridor, itself.  A difference of half a degree (F) can mean a world of difference with precipitation type (snow, freezing rain, sleet, or rain).  Admittedly, concern is growing for the potential of icing in this area before the deeper cold air can arrive and switch things over to snow.  On the other hand, should precipitation rates be heavy enough, it’s certainly possible these heavier rates will cool the entire column of air quicker than high resolution modeling currently suggests and a quicker transition to snow would result.  “Boom or bust” potential is higher than normal along the immediate I-70 corridor.

Given the above, and the potential of a “deformation band” of snow to develop during the 2nd half of the storm, our forecast snowfall totals remain unchanged.

Stay tuned and please know we’ll have another update posted Saturday morning.

The other big concern here is the fact that east-northeast winds will turn increasingly strong and gusty as the day gives way to afternoon and evening.  Winds may gust as high as 40 to 50 MPH at times during this time period as the storm heads off to the northeast.  Even if you accumulate an inch of snow, expect blowing and drifting issues to result.  Combine that with rapidly falling temperatures Saturday evening and the stage will be set for slick and hazardous travel throughout the region.

Much more in a few hours around this storm and additional “fun and games” that await next week… (Please send coffee ;-)).

Permanent link to this article: https://indywx.com/2019/01/19/late-friday-night-update/

Jan 18

Weekend Winter Storm Update…

After reviewing overnight and early morning data, our snowfall forecast remains unchanged.

We remain very concerned for the impact of a combination of heavy snow north of the I-70 corridor, strong and gusty winds, and plummeting temperatures.

Permanent link to this article: https://indywx.com/2019/01/18/weekend-winter-storm-update/

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